The chemical symbol for cobalt is Co. Cobalt is a transition metal that is commonly used in various industrial applications, including the production of batteries, hard metals, and magnets. It has a characteristic blue color when combined with certain other elements, leading to its use in ceramics and glassmaking. Cobalt is present in the Earth's crust and is usually obtained as a by-product of nickel and copper mining. Its properties, including strength and resistance to corrosion, make cobalt an important material in modern technology and manufacturing processes.